There may be geothermal vent communities, too.

Recently, a Russian research team reached the waters of Lake Vostok. Vostok is one of the largest lakes on Earth, but the body of water escaped attention for many years because it's buried under 3,700m of ice in Antarctica. There is no word yet on what has been found in the lake itself, but researchers now had a glimpse at the life present within it. That's because some of the lake's waters freeze onto the underside of a glacier that transits across the surface of the lake, trapping any organisms within it.

By sequencing the DNA and RNA trapped in the ice, the authors found what appears to be a diverse community of bacterial species, including some that suggest that Vostok has the equivalent of deep-sea hydrothermal vents. And, perhaps more intriguingly, it appears to have animals living under the ice.

The challenge with any of these studies is avoiding contamination (see, for example, the bigfoot genome). So, the authors of this paper took a rather extreme measure to eliminate it: they chilled some bleach and dipped the ice cores in that to wipe out anything that might have accumulated on the surface. They also froze some sterile water and treated it identically to the their ice core samples. These controls did produce some DNA sequences, but the vast majority of it was human, human acne bacteria, the E. coli bacteria used in labs, or, oddly, cow (maybe someone was eating lunch in lab that day?).

The DNA from the Vostok samples was much richer and more diverse than that. A huge range of bacterial species was present, including many groups that live in fresh and saltwater environments, in soil, and in sediments. There were even some unexpected finds. Cyanobacteria normally make a living by doing photosynthesis, but their DNA was found in the lake, which is buried under enough ice that light never reaches it. Archaea have picked up a reputation as extremophiles, but there were only two sets of sequence from them in the ice. The vast majority of the sequences were bacterial.

Some of the sequences come from bacterial groups that were first identified at deep-sea hydrothermal vents. Those are powered by volcanic activity, and the authors note that Vostok fills a rift valley, which might allow similar structures to form in the lake itself. Alternately, the bacteria could be living in water that seeps into hot areas under the lake bottom and sporadically get ejected into the lake.

But perhaps the biggest surprise is the presence of sequences that indicate multicellular life. Many of those are from fungi, but a number of them appear to be from animals, including arthropods, a mollusk, cnidarians, and crustaceans. A couple of factors support the idea that animals may be present. One is that members of these groups have been found at deep-sea hydrothermal vents. The second is that a number of bacterial species are either animal pathogens or part of the gut community.

All in all, the DNA pictures suggest there may be a large community of creatures living deep under the ice. What it doesn't make clear is if it's a thriving community (like that which we've seen at deep-sea vents) or a sparse one that's barely scraping by. DNA sequences can be suggestive, but there's always the chance that two closely related species have adapted to very different environments. So it's a bit dangerous to infer too much from the presence of some of the groups here. To really get a clear picture of life in the lake, we'll probably have to figure out a way to send something down to look.

Please please please let there be a sophisticated drilling probe to Europa within my lifetime.

Indeed. This feels like a rehearsal. But isn't the ice sheet in Europa a lot thicker than this? It's going to be one hell of a drill.

Yeah, probably beyond our current technology unless someone comes up with something exceedingly clever. But, IIRC, there are areas of Europa where it is believed that the ice sheet has upturned, bringing with it subsurface water. Those would be the areas I would target, were I planning such a mission.

By sequencing the DNA and RNA trapped in the ice, the authors found what appears to be a diverse community of bacterial species, including some that suggest that Vostok has the equivalent of deep-sea hydrothermal vents. And, perhaps more intriguingly, it appears to have animals living under the ice.

Shoggoths?

(Seriously, though, I'm also thinking of the implications this would have for Europa.)

Please please please let there be a sophisticated drilling probe to Europa within my lifetime.

Indeed. This feels like a rehearsal. But isn't the ice sheet in Europa a lot thicker than this? It's going to be one hell of a drill.

Yeah, probably beyond our current technology unless someone comes up with something exceedingly clever. But, IIRC, there are areas of Europa where it is believed that the ice sheet has upturned, bringing with it subsurface water. Those would be the areas I would target, were I planning such a mission.

Nah. It's only a matter of money and political will.Neither of which does the US have anymore.

More crippling, those that control the purse strings are totally risk-averse. Which is why NASA is tooting yet another Mars rover rather than going anywhere else.Hell, they nixed programs that would have put an observation blimp in the air -and a floating probe in a lake on Titan! Too much 'risk.'

My (totally uninformed) guess is that they find the lake has some good hydrothermal vents (hotsprings) and there is a solid little ecology at the bottom of this lake. I feel that for arthropods and other "multicells" to survive as long as the lake has been buried indicates a fairly stable ecology, but I am talking out of my ass here.

I don't think it would be too difficult to create a probe to drop down. The trick is making sure you can get it back (and that it's fully sterilized). The last thing we'd want to do is kill the creatures under the ice or introduce any kind of contamination.

Now that we know something is down there, maybe somebody will get busy building Ice Alvin Jr.

If it's all ice do you still need to drill? Make a sensor pod and cable that are all heated to stay above freezing temperature. Then just sit back and wait for the thing to melt its way to the bottom. Might take a few years, but that's not an unusual wait time for a space probe mission.

Please please please let there be a sophisticated drilling probe to Europa within my lifetime.

Indeed. This feels like a rehearsal. But isn't the ice sheet in Europa a lot thicker than this? It's going to be one hell of a drill.

Yeah, probably beyond our current technology unless someone comes up with something exceedingly clever. But, IIRC, there are areas of Europa where it is believed that the ice sheet has upturned, bringing with it subsurface water. Those would be the areas I would target, were I planning such a mission.

Nah. It's only a matter of money and political will.Neither of which does the US have anymore.

More crippling, those that control the purse strings are totally risk-averse. Which is why NASA is tooting yet another Mars rover rather than going anywhere else.Hell, they nixed programs that would have put an observation blimp in the air -and a floating probe in a lake on Titan! Too much 'risk.'

I'd be a lot more interested in seeing something like Curiosity on Titan than on Mars. Mars may have had some life on it long ago. Titan might have some now.

Bah. Who needs clever when you've got decommissioned plutonium? Slap a big-ass RTG on it, or even a small reactor. The electricity powers the drill, and the "waste" heat doesn't go to waste. When it reaches the ocean, leave big mama behind in the borehole, with an antenna for a tail, and send a secondary submersible out to explore. Also, radation during the trip from Earth sterilizes the probe.

I'm all for life on Europa too, but let's not forget that Antarctica has been located at various places on the Earth throughout history, and it would have been warm and covered in life. We don't know that any new life evolved there, just that some forms were able to adapt. It wouldn't be so easy on Europa.

Please please please let there be a sophisticated drilling probe to Europa within my lifetime.

Indeed. This feels like a rehearsal. But isn't the ice sheet in Europa a lot thicker than this? It's going to be one hell of a drill.

Yeah, probably beyond our current technology unless someone comes up with something exceedingly clever. But, IIRC, there are areas of Europa where it is believed that the ice sheet has upturned, bringing with it subsurface water. Those would be the areas I would target, were I planning such a mission.

Nah. It's only a matter of money and political will.Neither of which does the US have anymore.

More crippling, those that control the purse strings are totally risk-averse. Which is why NASA is tooting yet another Mars rover rather than going anywhere else.Hell, they nixed programs that would have put an observation blimp in the air -and a floating probe in a lake on Titan! Too much 'risk.'

I'd be a lot more interested in seeing something like Curiosity on Titan than on Mars. Mars may have had some life on it long ago. Titan might have some now.

Me too. But based on surface conditions, I don't know if wheels could get any traction. Where Huygens landed from what I understand, it was like a chocolate crust over ice cream. And then there are those 300 foot high dunefields made out of who knows what.You really want to spend six years getting a probe out there to have it flop upside down in a swamp?

In my humble opinion, an aerial survey and a lake probe make more sense. Then, once stable surfaces are defined, that's when you put a rover down. And I'd give up sex to be selected to drive it.

If it's all ice do you still need to drill? Make a sensor pod and cable that are all heated to stay above freezing temperature. Then just sit back and wait for the thing to melt its way to the bottom. Might take a few years, but that's not an unusual wait time for a space probe mission.

If you can find a power supply that will heat for that long, then yes. It would also freeze behind itself, solving any concerns about contamination (besides the probe itself).

If it's all ice do you still need to drill? Make a sensor pod and cable that are all heated to stay above freezing temperature. Then just sit back and wait for the thing to melt its way to the bottom. Might take a few years, but that's not an unusual wait time for a space probe mission.

That would require an incredible amount of energy to generate enough heat the entire length of the cable required to get all the way through the ice.

Assume the ice at the top of the crust is -160C and the water below is 0C. The crust is 100 Kmeters thick. Assume also that the hole to be melted to contain the probe is only a square centimeter. It takes 4.6 joules per 1 cubic centimeter to heat the ice one degree C. (I love working in metric standard units!) That means it will take at least 73.6 billion joules of heat to melt a hole all the way through to the internal water layer, assuming no losses to the surrounding ice, etc.

The equation is: 10E6 (crust thickness in cm) * 160C * 4.6 joules/ccH20 = 73.6E9 In other words you'll need a nuclear power source for the heat/electrical power. Solar panels do not work very well that far out. The sun is a bright dot of light.

It would be easier to grab an asteroid, put a rocket engine on it and blast it at Europa. When it hits the moon, shove your sensors and whatever in the hole before it re-freezes.

Another idea might be to engineer a tunneling machine like what they used recently for new subway tunnels in New York. Once it gets to the water it will break free and deliver the sub-ice science package. In any case, there will need to be a pressure dome over the entry point that will come under a tremendous amount of pressure from the enclosed water. It will be a Deepwater Horizon blowout otherwise. Europa has little atmosphere, its practically vacuum. Maybe the drilling machine can payout a small tube to contain a cable to connect the science package to the surface of Europa.

But in any case there will be an incredible amount of power needed to do the "drilling" and its not going to be as easy as what we saw on "Armageddon". (one of the the most ridiculous NON-science fiction movies ever made!) By the time it happens on Europa for real, Bruce Willis will be at best a memory.

Has there ever been a proposal for a Europa probe that didn't revolve around some sort of RTG/Nuclear power scheme for the probe?

I don't know but the typical RTGs that have been used don't have the power required. There aren't any left, NASA used the last one a while back for the Pluto mission. They've been negotiating with the Russians to have them make some Plutonium in their breeder reactor from a few missile warheads.

They mix the plutonium with relatively inert material and the heat given off as the plutonium decays to uranium 238 is the power source used by the Peltier devices to generate electricity. Very inefficient. It might be smarter to use the heat directly and have the RTG become the "melting device".

Absolutely fascinating. It's estimated that the lake has been isolated for 15-odd million years. Exchange with the Earth's biosystem would have been at an absolute minimum since then. Finding life down there, maybe even very, very strange life, would bode well for an ecosystem on Europa (as some here have already mentioned).

The thickness is unknown, but it is the goal of upcoming JUICE to measure it (if not too thick). Given the heat flow, there are AFAIK two main possibilities. A thicker (100s of km) convective ice, or a thinner (1s of km) conducting ice.

But IIRC models of regions of upturned sheets have the ice (at least over subsurface water) as comparable to the ice sheet over Vostok, i.e. 3-4 km.

All in all, the DNA pictures suggest there may be a large community of creatures living deep under the ice.

Correct me if I am wrong, but from my quick browse of the paper they actually sequenced the cDNA from the isolated RNA. Therefore this is good proof that there is (well actually was, when the lake water froze onto the ice that they sampled) active microbial and animal life, as the RNA will rapidly degrade in any environment.

Exciting study, however perhaps a bit light on the actual sequencing data. I think they could have easily produced more reads and therefore decreased the detection limit to e.g. see more sequences Archeal origin.

"Reactor-grade plutonium from spent nuclear fuel contains various isotopes of plutonium. Pu-238 makes up only a percent or two, but may be responsible for much of the short-term decay heat because of its short half-life. This is not useful for producing Pu-238 for RTGs because difficult isotopic separation would be needed.

Pure plutonium-238 is prepared by irradiation of neptunium-237, one of the minor actinides that can be recovered from spent nuclear fuel during reprocessing, or by the irradiation of americium[1] in a reactor."